We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense spec...We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense speckle pattern of near field with thickly dotted hot spots is observed at the end of propagation with an intensity-length product above 17 TW/cm.The Stokes developing from the scattering of the laser beam by quantum fluctuations is characterized by a combination of high spatial frequency components.The observed speckle pattern with small-diameter hot spots results from the combination of the nonlinear Raman amplification and the linear diffraction propagation effect of the Stokes with a noise pattern arising from the spontaneous Raman scattering.A new promising suppression concept based on the special characteristic of the Stokes,called active and selective filtering of Stokes,is proposed.展开更多
In the highest-power chirped-pulse amplification lasers, the pulse must be stretched in time, amplified, compressed in a grating compressor and subsequently focused by off-axis parabola to obtain a high peak power. In...In the highest-power chirped-pulse amplification lasers, the pulse must be stretched in time, amplified, compressed in a grating compressor and subsequently focused by off-axis parabola to obtain a high peak power. In the optical terminal, the temporal and spatial effects of mismatched multigrating tiled compressor on the far-field pulse are critical factors to be analysed. In this paper, a k-space raytracing model is proposed for the temporal and spatial analyses of possible errors in a four-grating single-pass tiled compressor. The results show that the last grating affects mainly the partial focal spot, while the middle two gratings affect the temporal waveform, and the partial focal spot needs much higher error control than that in the temporal domain in a picosecond pulse compression.展开更多
文摘We report the experimental investigation of a stimulated rotational Raman scattering effect in long air paths on SG-III TIL,with a 1053 nm,20-cm-diameter,linearly polarized,3 ns flat-topped laser pulse.An intense speckle pattern of near field with thickly dotted hot spots is observed at the end of propagation with an intensity-length product above 17 TW/cm.The Stokes developing from the scattering of the laser beam by quantum fluctuations is characterized by a combination of high spatial frequency components.The observed speckle pattern with small-diameter hot spots results from the combination of the nonlinear Raman amplification and the linear diffraction propagation effect of the Stokes with a noise pattern arising from the spontaneous Raman scattering.A new promising suppression concept based on the special characteristic of the Stokes,called active and selective filtering of Stokes,is proposed.
基金Project supported by the National High Technology Research and Development Program of China(Grant No.2009AA8044005)
文摘In the highest-power chirped-pulse amplification lasers, the pulse must be stretched in time, amplified, compressed in a grating compressor and subsequently focused by off-axis parabola to obtain a high peak power. In the optical terminal, the temporal and spatial effects of mismatched multigrating tiled compressor on the far-field pulse are critical factors to be analysed. In this paper, a k-space raytracing model is proposed for the temporal and spatial analyses of possible errors in a four-grating single-pass tiled compressor. The results show that the last grating affects mainly the partial focal spot, while the middle two gratings affect the temporal waveform, and the partial focal spot needs much higher error control than that in the temporal domain in a picosecond pulse compression.
